Mobile phone capable of stopping main clock signal

ABSTRACT

A mobile phone has at least one main clock system and operating based on a main clock signal of the main clock system. The main clock system includes a main counter for counting main clocks of the main clock signal; and a power saving section for stopping generation of the main clock signal for a time period, while counting wait clocks of a wait clock signal, for restarting the generation of the main clock signal after the time period, and for controlling the main counter the main counter based on the counted wait clocks as if the main counter always counts the main clocks of the main clock signal.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a mobile phone, and more particularlyto a technique which suppresses power consumption in a waiting operationof a mobile phone.

2. Description of the Related Art

Conventionally, a mobile phone has been come into a practical use. Inthe mobile phone, a waiting operation peculiar to the mobile phone iscarried out in addition to a usual operation such as speechcommunication and data communication. A substantial function of themobile phone is not realized during the waiting operation. Therefore, acontrol is carried out during the waiting operation to prevent powerconsumption of a battery.

A control unit used in a conventional mobile phone will be describedwith reference to FIG. 1. The conventional control unit is composed of acentral processing unit (CPU) 10, a main clock generator 11, a waitclock generator 12, a wait timer 13 and a main counter 14.

The main clock generator 11 generates a main clock signal to operate thecontrol unit and supplies to the CPU 10 and the main counter 14. The CPU10 operates in response to the main clock signal to control the wholecontrol unit of the mobile phone. The main counter 14 carries out acounting operation in response to the main clock. The CPU 10 controlscommunication between a base station and the mobile phone in accordancewith the count value of the main counter 14.

The wait clock generator 12 generates a wait clock signal and suppliesto the wait timer 13. The wait timer 13 operates in response to the waitclock. The wait timer 13 generates a start signal and supplies to themain clock generator 11. Also, the wait timer 13 generates aninterruption signal and supplies to the CPU 10. Thus, the wait timer 13controls an operation before and after a waiting operation.

In the above configuration, the operation of the control unit of theconventional mobile phone will be described. The CPU 10 specifies a waittime before entering the waiting operation, and then issues a main clockstop instruction to the main clock generator 11. Also, the CPU 10 issuesa wait timer start instruction to the wait timer 13. By this, the mainclock generator 11 stops the generation of the main clock signal. As aresult, the CPU 10 enters a sleep mode and the counting operation of themain counter 14 is stopped.

When the specified wait time elapses in the sleep mode, the wait timer13 supplies a start signal to the main clock generator 11 to restartsthe main clock generator 11 and supplies an interruption signal to theCPU 10 to restart the operation of the CPU 10. Thus, the countingoperation of the main counter 14 is restarted and the CPU 10 cancommunicate with a base station in accordance with the count value ofthe main counter 14. The power consumption of a battery can besuppressed because the main clock signal is stopped in the waitingoperation through above operation. However, the count value of the maincounter becomes discrete before and after the waiting operation.

By the way, in the frequency division multiple access (FDMA) and thetime division multiple access (TDMA) which are adopted in theconventional mobile phone, because the status of the CPU can begenerally changed from the waiting operation in accordance with thereception of electric wave from the base station, there is not aproblem, even if the count value of the main counter become discrete.

Also, in the mobile phone of the code division multiple access (CDMA)system, continuity of the count value of the main counter before andafter the waiting operation is required. However, the main clock signalis low in frequency and is near the frequency of the wait clock signal.For this reason, it is possible to correct the count value of the maincounter by searching for a few clocks to maintain the continuity of thecount value of the main counter.

However, in the wide band—code division multiple access (W-CDMA),because the frequency of a main clock signal is high considerably,compared with the frequency of the wait clock. For this reason, it isimpossible to correct the count value of the main counter to maintainthe continuity of the count value before and after the waitingoperation. Moreover, in the W-CDMA system, it is not possible to carryout communication if the count value of the main counter is shifted byone clock. Therefore, in the W-CDMA system, it is necessary that themain clock signal is not stopped even during the wait operation or thecommunication synchronization with the base station is established againafter the wait operation.

If it is supposed that the main clock signal is not stopped during thewait operation, the power consumption during the wait operation becomeslarger tens of times, compared with the case where the main clock signalis stopped. Also, if it is supposed that the communicationsynchronization is established again after the wait operation, a processtime after the wait operation becomes 10 times or more, resulting inincrease of the power consumption.

SUMMARY OF THE INVENTION

Therefore, an object of the present invention is to provide a mobilephone in which the power consumption can be suppressed.

Another object of the present invention is to provide a mobile phone inwhich a main clock signal can be stopped during a waiting operation.

Still another object of the present invention is to provide a mobilephone in which a process time after a waiting operation can bedecreased.

In an aspect of the present invention, a mobile phone has at least onemain clock system and operating based on a main clock signal of the mainclock system. The main clock system includes a main counter for countingmain clocks of the main clock signal; and a power saving section forstopping generation of the main clock signal for a time period, whilecounting wait clocks of a wait clock signal, for restarting thegeneration of the main clock signal after the time period, and forcontrolling the main counter the main counter based on the counted waitclocks as if the main counter always counts the main clocks of the mainclock signal.

Here, the power saving section may include a stop control section, acorrection control section and a restart control section. The stopcontrol section stops the generation of the main clock signal. Thecorrection control section counts the wait clocks of the wait clocksignal for the time period during which the generation of the main clocksignal is stopped, and corrects a count value of the main counter basedon the counted wait clocks. The restart control section restarts thegeneration of the main clock signal after the time period elapses, suchthat the main counter counts the main clocks from the corrected countvalue.

Also, it is desirable that the frequency of the main clock signal islarger than a frequency of the wait clock signal.

Also, the time period during which the generation of the main clocksignal is stopped is desirably predetermined.

Also, the correction control section may include a counting section forcounting the wait clocks of the wait clock signal for the time periodduring which the generation of the main clock signal is stopped; acalculating section for calculating the main clocks while the generationof the main clock signal is stopped; and a setting section forcorrecting the count value of the main counter based on the calculatedmain clocks. In this case, the calculating section may include a ratiosection, a read section and another section. The ratio sectiondetermines a frequency ratio of a frequency of the main clock signal toa frequency of the wait clock signal. The read section reads out a countvalue from the main counter when the generation of the main clock signalis stopped. The other section calculates the main clocks while thegeneration of the main clock signal is stopped, based on the countedwait clocks of the wait clock signal.

At this time, the mobile phone may further include a battery; and afirst driving section for driving the ratio section when a voltage ofthe battery changes. Otherwise, the mobile phone may further include atemperature sensor; and a second driving section for driving the ratiosection when the temperature sensor senses change of a temperature ofthe mobile phone.

Also, the mobile phone may include first and second main clock systems,each of which is configured as mentioned above. In this case, the waitclock signal is shared by the first and second main clock systems.

In another aspect of the present invention, a mobile phone has at leastone main clock system. The main clock system includes a main clockgenerator which generates a main clock signal; a main counter whichcarries out a counting operation of main clock of the main clock signalin response to the main clock signal generated by the main clockgenerator; and a processor which stops the counting operation of themain counter by stopping the generation of the main clock by the mainclock generator before entering a waiting operation and changes a countvalue of the main counter as if the counting operation of the maincounter has been not stopped when going out of the waiting operation.

Here, the processor may include a wait timer which carries out acounting operation of wait clocks of a wait clock signal in response toa wait clock signal for a predetermined time corresponding to a timeperiod during which the generation of the main clock signal is stopped;and a CPU which operates based on the count value of the main counter inresponse to the main clock signal. In this case, the wait timer may stopthe operations of the main counter and the CPU by stopping thegeneration of the main clock signal by the main clock generator inresponse to an instruction from the CPU. Also, the wait timer maycontrol the main clock generator to restart the generation of the mainclock signal and the CPU to change a count value of the main counter,after the predetermined time elapses.

Also, the CPU may change the count value of the main counter by addingdata corresponding to the number of the main clocks while the countingoperation of the main counter is stopped, to the count value of the maincounter. In this case, the CPU may calculate the data to be added, basedon the wait clocks counted by the wait timer during the predeterminedtime. Also, the processor may further include a clock precision unitwhich holds a ratio of a frequency of the main clock signal to afrequency of the wait clock signal. The CPU calculates the data bymultiplying the wait clocks counted by the wait timer by the ratio heldby the clock precision measuring unit.

Also, it is desirable that the predetermined time is set in the waittimer by the CPU before the wait timer stops the generation of the mainclock signal by the main clock generator.

In still another aspect of the present invention, a mobile phone has twomain clock systems, each of which include a main clock generator whichgenerates a main clock signal; a main counter which carries out acounting operation of main clock of the main clock signal in response tothe main clock signal generated by the main clock generator; and aprocessor which stops the counting operation of the main counter bystopping the generation of the main clock by the main clock generatorbefore entering a waiting operation and changes a count value of themain counter as if the counting operation of the main counter has beennot stopped when going out of the waiting operation.

Here, the processor may include a wait timer which carries out acounting operation of wait clocks of a wait clock signal in response toa wait clock signal for a predetermined time corresponding to a timeperiod during which the generation of the main clock signal is stopped;and a CPU which operates based on the count value of the main counter inresponse to the main clock signal.

Also, the wait timer may be shared by the two main clock systems.

In yet still another aspect of the present invention, a method of savingpower consumption in a mobile phone having at least one main clocksystem and operating based on a main clock signal of the main clocksystem, is attained by (a) counting main clocks of the main clocksignal; by (b) stopping generation of the main clock signal for a timeperiod, while counting wait clocks of a wait clock signal; by (c)restarting the generation of the main clock signal after the timeperiod; and by (d) restarting the counting operation of the main clockof the main clock signal from preset data corresponding to the countedwait clocks of the wait clock signal.

The step (b) may be attained by (e) counting the wait clocks of the waitclock signal for the time period; by (f) calculating the preset databased on a count value of the main counter based on the counted waitclocks of the wait clock signal; and by (g) setting the preset data.

Also, the frequency of the main clock signal is desirably larger thanthe frequency of the wait clock signal, and the time period is desirablypredetermined.

Also, the step (f) may be attained by (h) determining a frequency ratioof a frequency of the main clock signal to a frequency of the wait clocksignal; by multiplying the counted wait clocks of the wait clock signalby the frequency ratio; and by adding the counted main clocks when thegeneration of the main clock signal is stopped, to the multiplyingresult. In this case, the method may further include the step of:carrying the step (h) when a voltage of a battery changes, or carryingthe step (h) when a temperature of the mobile phone changes.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram showing the circuit structure of a conventionalmobile phone;

FIG. 2 is a block diagram showing the circuit structure of a mobilephone according to a first embodiment of the present invention;

FIG. 3 is a flow chart to show the operation of the mobile phone in thefirst embodiment of the present invention;

FIG. 4 is a diagram showing waveforms during the operation of the mobilephone in the first embodiment of the present invention; and

FIG. 5 is a block diagram showing the circuit structure of the mobilephone according to a second embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, a mobile phone of the present invention will be describedin detail with reference to the drawings.

FIG. 2 is a block diagram showing the circuit structure of the mobilephone according to the first embodiment of the present invention. Themobile phone is comprised of a CPU 10, a main clock generator 11, a waitclock generator 12, a wait timer 13, a main counter 14 and a clocksignal precision measuring unit 15. A CPU bus 20 connects the CPU 10,the main clock generator 11, the wait timer 13, the main counter 14 andthe clock signal precision measuring unit 15 mutually.

The CPU 10 controls the whole of the mobile phone. The processingcarried out by the CPU 10 is described in detail later.

The main clock generator 11 generates a main clock signal to enable thewhole operation of the mobile phone. The generation of the main clocksignal is controlled based on a start signal outputted from the waittimer 13. The main clock signal generated by the main clock generator 11is supplied to the CPU 10, the main counter 14 and the clock signalprecision measuring unit 15. The main clock signal is a rectangular wavesignal whose frequency is about 4 MHz, as shown in FIG. 4A. The mainclock signal is kept a low level in a portion of the waveform shown inFIG. 4A, and the time interval in the low level is called a wait statein which the main clock signal is stopped and a waiting operation iscarried out in the mobile phone.

The wait clock generator 12 generates a wait clock signal to control thewaiting operation. The wait clock signal is called a real time clocksignal, and is a rectangular wave signal whose frequency is about 32 KHzas shown in FIG. 3(B). Unlike the main clock signal, the wait clocksignal is never stopped, and is always generated. The wait clock signalgenerated by the wait clock generator 12 is supplied to the wait timer13 and the clock signal precision measuring unit 15.

The wait timer 13 operates based on the wait clock signal from the waitclock generator 12. The wait timer 13 generates the start signal whenthe time specified by the CPU 10 elapses. The wait timer 13 supplies thestart signal to the CPU 10 and the main clock generator 11. The startsignal is used to start the generation of the main clock signal by themain clock generator 11.

Also, the wait timer 13 generates and supplies a control signal to themain counter 14. The control signal is set to the low level when thewait timer 13 receives a wait timer start instruction from the CPU 10and is set to a high level when the count of the wait timer 13 reaches afull value.

When the control signal is set to the low level, the main counter 14becomes a hold state and stops the counting operation. In the holdstate, it is possible to set a new count value to the main counter 14.Also, the main counter 14 restarts the counting operation from the setcount value when the control signal is set to the high level.

Thus, the main counter 14 is used to manage the whole timings from thebeginning of the communication to the end. The CPU 10 communicates withthe base stations in accordance with the count value of the main counter14. Although the main counter 14 sometimes is stopped as describedlater, the mobile phone is controlled in such a manner that the basestation can recognize the main counter 14 being always operating.

The clock signal precision measuring unit 15 calculates the ratio RATIOof the frequency of the main clock signal from the main clock generator11 to the frequency of the wait clock signal from the wait clockgenerator 12. The ratio RATIO calculated by the clock signal precisionmeasuring unit 15 is sent to the CPU 10 through the CPU bus 20.

Next, the operation of the mobile phone configured as mentioned abovewill be described with reference to FIGS. 3 and 4. It should be notedthat the change from an ordinary operation to the waiting operation inthe sleep mode and the restart operation going out from the waitingoperation to the waiting operation will be described mainly.

The CPU 10 issues the wait timer start instruction to the wait timer 13as shown at Step S10 of FIG. 3 when the CPU 10 enters the waitingoperation. The wait timer start instruction is issued in a suitabletiming before entering the waiting operation, as shown in the timing P2of FIG. 4C. Also, the CPU 10 sends to the wait timer 13, data defining atime until the main clock signal is restarted, simultaneously with theissuance of the wait timer start instruction. The data is composed ofthe number WV of clocks of the wait clock signal.

The wait timer 13 is started in response to the issuance of the waittimer start instruction, as shown at Step S20 of FIG. 3. That is, asshown in FIG. 4D, when receiving the wait timer start instruction, thewait timer 13 starts the counting operation from the wait clock of thewait clock signal arriving after the timing P3 of FIG. 4C. At the sametime, the wait timer 13 sets the control signal to the low level, asshown in FIG. 4F. Thus, the main counter 14 enters the HOLD state, asshown at Step S30 of FIG. 3. That is, the main counter 14 stops thecounting operation, as shown in FIG. 4G, and holds the count value atthe point.

After that, the wait timer 13 generates and supplies a sleep signal (notshown) to the CPU 10 and the main clock generator 11. Thus, as shown inFIG. 4A, the main clock signal is stopped (step S21) and the CPU 10enters the sleep mode (Step S11).

The wait clocks sent while the main clock signal is stopped after theissuance of the wait timer start instruction are counted for the numberWV by the wait timer 13. It is preferable that the number WV of waitclocks includes a loss for the restarting operation. When counting thewait clocks for the number MW, the wait timer 13 activates the startsignal to the high level as shown in FIG. 4E, and sends to the CPU 10and the main clock generator 11. In response to the start signal, themain clock generator 11 restarts the generation of the main clock signalas shown in FIG. 4A (Step S22). Also, the sleep mode of the CPU 10 iscanceled at the timing P4 shown in FIG. 4 (Step S12). Thus, the CPU 10restarts operation.

Next, when restarting the operation, the CPU 10 reads the count valueheld by the main counter 14 at the timing P5 of FIG. 4C (Step S13). Thatis, the main counter 14 sends the count value held at that time point tothe CPU 10 via the CPU bus 20 (Step S31).

Next, the CPU 10 calculates a new counter value RV (Step S14). The newcounter value RV is calculated in accordance with the followingequation:RV=HV+WV×RATIOwhere HV is a count value held by the main counter 14, WV is the numberof wait clocks generated while the main counter 14 is stopped, and RATIOis the ratio of the frequency of the main clock signal previouslymeasured by the clock signal precision measuring unit 15 to thefrequency of the wait clock signal. For example, the calculation ofratio RATIO is carried out at the timing P1 of FIG. 4. The number ofmain clocks while the main counter 14 is stopped is calculated from theequation of “WV×RATIO”.

Next, the CPU 10 sets the calculated new counter value RV to the maincounter 14 at the timing P6 of FIG. 4C (Step S15). Thus, the new countervalue RV is set to the main counter 14 (Step S32).

After that, when the wait timer 13 becomes full, the wait timer 13 setsthe control signal to the high level and instructs the main counter 14to restart (Step S23). Thus, the counting operation of the main counter14 is restarted (Step S33). The count value of the main counter 14 atthis time point is coincident with the count value which would becounted by the main counter 14 when the generation of the main clocksignal is not stopped. Therefore, the following process can be istreated as the main clock signal is continuously outputted and the maincounter 14 continues the counting operation.

Because the frequencies of the main clock signal and the wait clocksignal are previously determined, the ratio RATIO of the frequencies ofthese clocks should be constant. However, the frequencies of the mainclock signal and the wait clock signal change in accordance with thetemperature and the voltage. It should be noted that the above mentionedmeasurement of the ratio RATIO of the frequency of the main clock signalto the frequency of the wait clock signal by the clock signal precisionmeasuring unit 15 is carried out when a temperature detector or avoltage detector (both not shown) incorporated in the mobile phonedetects the change in temperature or voltage.

The new counter value RV is calculated in accordance with the abovecalculation equation when the frequencies of the main clock signal andthe wait clock signal change. There is a possibility that the calculatednew counter value RV has an error for a few clocks because the mainclock signal is high in frequency. When the error is generated, themobile phone cannot keep the continuity of the count value of the maincounter 14 and especially the mobile phone of the W-CDMA system willfall in the operation impossible state. Therefore, to prevent the errorin the mobile phone according to the first embodiment, the ratio RATIOis calculated and is held by the clock signal precision measuring unit15 when the temperature change or the voltage change is detected. Theheld ratio RATIO is used for the calculation of the new counter valueRV. As a result, because any error is never contained in the calculatednew counter value RV, the continuity of the count value of the maincounter 14 is kept and the mobile phone can continue the normaloperation.

As described above, according to the mobile phone in the firstembodiment, when the present invention is applied to the mobile phone ofthe W-CDMA system, the power consumption can be suppressed because thecontinuity of the main counter can be kept even if the generation of themain clock signal is stopped in the waiting operation. Moreover, becauseit is not necessary to establish communication synchronization with thebase station again, it is possible to reduce the process time after thewaiting operation and suppression of the power consumption.

The mobile phone according to the second embodiment of the presentinvention has the main clock signal of 2 systems will be described.

FIG. 5 is a block diagram showing the circuit structure of the mobilephone according to the second embodiment of the present invention. Themobile phone is composed of a first CPU 10 a, a first main clockgenerator 11 a, a wait clock generator 12, a wait timer 13, a first maincounter 14 a, a first clock signal precision measuring unit 15 a, asecond CPU 10 b, a second main clock generator 11 b, a second maincounter 14 b, and a second clock signal precision measuring unit 15 b.The first CPU 10 a, the first main clock generator 11 a, the first waittimer 13 a, the first main counter 14 a and the first clock signalprecision measuring unit 15 a are mutually connected by a first CPU bus20 a. Also, the second CPU 10 b, the second main clock generator 11 b,the second wait timer 13 b, the second main counter 14 b and the secondclock signal precision measuring unit 15 b are mutually connected by asecond CPU bus 20 b.

The first CPU 10 a, the first main clock generator 11 a, the wait clockgenerator 12, the wait timer 13, the first main counter 14 a and thefirst clock signal precision measuring unit 15 a of a first systemsection correspond to the CPU 10, the main clock generator 11, the waitclock generator 12, the wait timer 13, the main counter 14 and the clocksignal precision measuring unit 15 in the first embodiment,respectively. The functions and operations of them are also the same asthose of corresponding ones in the fist embodiment. Also, the second CPU10 b, the second main clock generator 11 b, the wait clock generator 12,the wait timer 13, the second main counter 14 b and the second clocksignal precision measuring unit 15 b of a second system sectioncorrespond to the CPU 10, the main clock generator 11, the wait clockgenerator 12, the wait timer 13, the main counter 14 and the clocksignal precision measuring unit 15 in the first embodiment,respectively. The functions and operations of them are also the same asthose of corresponding ones in the fist embodiment.

According to the mobile phone in the second embodiment, because twokinds of the main clock signals can be handled, there is an advantagethat the generality further spreads. It should be noted that the mainclock signal is not limited to two kinds and may be three or more kinds.In the case, the mobile phone having multiple system of main clocksignal can be achieved by adding sets of the CPU, the main clockgenerator, the main counter and the clock signal precision measuringunit in accordance with the number of systems.

As described above in detail, according to the present invention, themobile phone can be provided in which the power consumption can besuppressed and the process time after the waiting operation can bedecreased.

1. A mobile phone having at least one main clock system and operating based on a main clock signal of said main clock system, wherein said main clock system comprising: a main counter configured to count main clocks of said main clock signal; and a power saving circuit configured to stop generation of said main clock signal for a time period, while counting wait clocks of a wait clock signal, to restart the generation of said main clock signal after the time period, and to control said main counter based on the counted wait clocks as if said main counter always counts said main clocks of said main clock signal, wherein said power saving circuit comprises: a correction controller configured to count said wait clocks of said wait clock signal for the time period during which the generation of said main clock signal is stopped, and to correct a count value of said main counter based on the counted wait clocks, said correction controller comprises: a single counter configured to count said wait clocks of said wait clock signal for the time period during which the generation of said main clock signal is stopped; and a calculator configured to calculate said main clocks while the generation of said main clock signal is stopped; and a setting circuit configured to correct the count value of said main counter based on the calculated main clocks.
 2. The mobile phone according to claim 1, wherein said power saving circuit further comprises: a stop controller configured to stop the generation of said main clock signal; and a restart controller configured to restart the generation of said main clock signal after said time period elapses, such that said main counter counts said main clocks from the corrected count value.
 3. The mobile phone according to claim 1, wherein a frequency of said main clock signal is larger than a frequency of said wait clock signal.
 4. The mobile phone according to claim 1, wherein the time period during which the generation of said main clock signal is stopped is predetermined.
 5. The mobile phone according to claim 1, wherein said calculator comprises: a ratio calculator configured to determine a frequency ratio of a frequency of said main clock signal to a frequency of said wait clock signal; a CPU reading out a count value from said main counter when the generation of said main clock signal is stopped, and calculating said main clocks while the generation of said main clock signal is stopped, based on the counted wait clocks of said wait clock signal.
 6. The mobile phone according to claim 5, further comprising: a battery; and said ratio calculator calculates when a voltage of said battery changes.
 7. The mobile phone according to claim 5, further comprising: a temperature sensor; and said ratio calculator calculates when said temperature sensor senses change of a temperature of said mobile phone.
 8. The mobile phone according to claim 1 comprising first and second main clock systems, each of which is same as said main clock system.
 9. The mobile phone according to claim 8, wherein said wait clock signal is shared by said first and second main clock systems.
 10. A mobile phone having at least one main clock system, said main clock system comprising: a main clock generator which generates a main clock signal; a single main counter which carries out a counting operation of main clock of said main clock signal in response to said main clock signal generated by said main clock generator; and a processor which stops the counting operation of said main counter by stopping the generation of said main clock by said main clock generator before entering a waiting operation and changes a count value of said main counter as if the counting operation of said main counter has been not stopped when going out of the waiting operation, said change is based upon a preset value include a ratio of the frequency of the main clock signal to the frequency of the wait clock signal. wherein said processor comprises: a wait timer which carries out a counting operation of wait clocks of a wait clock signal in response to a wait clock signal for a predetermined time corresponding to a time period during which the generation of said main clock signal is stopped; and a CPU which operates based on the count value of said main counter in response to said main clock signal, said CPU changes the count value of said main counter by adding data corresponding to the number of said main clocks while the counting operation of said main counter is stopped, to the count value of said main counter, said CPU calculates said data to be added, based on said wait clocks counted by said wait timer during said predetermined time, said processor further comprises: a clock precision unit which holds a ratio of a frequency of said main clock signal to a frequency of said wait clock signal, and said CPU calculates said data by multiplying said wait clocks counted by said wait timer by said ratio held by said clock precision measuring unit.
 11. A method of saving power consumption in a mobile phone having at least one main clock system and operating based on a main clock signal of said main clock system, wherein said method comprising; (a) counting main clocks of said main clock signal using a first single counting means; (b) stopping generation of said main clock signal for a time period, while counting wait clocks of a wait clock signal using a second single counting means; (c) restarting the generation of said main clock signal after the time period; and (d) restarting the counting operation of said main clock of said main clock signal from preset data corresponding to said counted wait clocks of said wait clock signal, said preset data includes a ratio of the frequency of the main clock signal to the frequency of the wait clock signal, wherein said (b) restarting comprises: (e) counting said wait clocks of said wait clock signal for the time period; (f) calculating said preset data based on a count value of said main counter based on said counted wait clocks of said wait clock signal; and (g) setting said preset data, said (f) calculating comprises (h) determining the frequency ratio of a frequency of said main clock signal to a frequency of said wait clock signal; (i) multiplying said counted wait clocks of said wait clock signal by said frequency ratio; and (j) adding the counted main clocks when the generation of said main clock signal is stopped, to the multiplying result.
 12. The method according to claim 11, further comprising carrying said (h) determining when a voltage of a battery changes.
 13. The method according to claim 11, further comprising carrying said (h) determining when a temperature of said mobile phone changes.
 14. A mobile phone having at least one main clock system and operating based on a main clock signal of said main clock system, wherein said main clock system comprising: a main counter configured to count main clocks of said main clock signal; a wait counter configured to count wait clocks of wait clock signal; a precision measuring unit configured to calculate said frequency of ratio between said main clock signal and said wait clock signal; and a controller configured to stop and restart said generation of said main clock signal, and to reload a value to said main counter prior to restarting said generation of said main clock signal, wherein said value is calculated according to both the time period which said generation of said main clock is stopped and said frequency ratio between said main clock signal and said wait clock signal.
 15. The mobile phone claimed in claim 14, further comprising: a temperature sensor, wherein said precision measuring unit calculates said frequency ratio between said main clock signal and said wait clock signal when temperature sensor detects temperature change.
 16. The mobile phone claimed in claim 14, further comprising: a battery, wherein said precision measuring unit calculates said frequency ratio between said main clock signal and said wait clock signal when said battery detects the voltage change.
 17. The mobile phone according to claim 14, wherein a frequency of said main clock signal is larger than a frequency of said wait clock signal.
 18. The mobile phone according to claim 14, wherein the time period which the generation of said main clock signal is stopped is variable.
 19. The mobile phone according to claim 14 comprising first and second main clock systems each of which is same as said main clock system.
 20. A mobile phone according to claim 19, wherein said wait clock signal is shared by said first and second main clock systems. 